Taxon Account

Cocconeis pediculus Ehrenberg; 1838; 194

Key references

Jahn R., Kusber W.-H., Romero O.E. 2009. Cocconeis pediculus EHRENBERG and C. placentula EHRENBERG var. placentula (Bacillariophyta): Typification and taxonomy. Fottea. 9(2): 275-288.

Morphology

Shape
Valves broadly elliptical with obtuse apices; valve faces strongly curved, raphe valve concave, rapheless valve convex, flexed in girdle view.

Symmetry
Valves isopolar and bilaterally symmetrical.

Valve
Frustules heterovalvar, one valve with raphe, one valve without raphe.

Striae
Raphe valve with striae comprising dot-like areolae, parallel or slightly radiate at valve centre, more strongly radiate towards the apices, striae end before valve margin which is defined by a hyaline rim;
on rapheless valve striae appear transapically elongate in LM sometimes forming undulating longitudinal lines, striae slightly radiate at centre, more strongly radiate towards the apices, marginal ends of striae not visible because of valve curvature.

Axial area
Straight, narrow linear on the raphe valve terminating shortly before the valve apices; on the rapheless valve straight, linear axial area, depending on the focus it can be surrounded by a lyra-shaped hyaline area which is present on the inside of the valve.

Central area
On raphe valve small circular and slightly asymmetric due to slightly shorter central stria on one side; absent on rapheless valve.

Raphe
Straight with slightly expanded proximal endings, terminating before apices without any deflection.

Literature

References are given in chronological order.

Reference
Citation
Ehrenberg C.G. 1838. Die Infusionsthierchen als vollkommene Organismen. Ein Blick in das tiefere organische Leben de Natur. Verlag von Leopold Voss, Leipzig. 1-xvii, 1-548 pp; 1-64 pls Type Illustration; Morphology; Description
Gerloff J., Rivera P. 1979. Der submikroskopische Bau der Schalen von Cocconeis pediculus (Bacillariophyceae). Willdenovia. 9: 99-110. Morphology; Illustrations
Jahn R., Kusber W.-H., Romero O.E. 2009. Cocconeis pediculus EHRENBERG and C. placentula EHRENBERG var. placentula (Bacillariophyta): Typification and taxonomy. Fottea. 9(2): 275-288. Morphology; Type Illustration; Description
This page should be cited as:

Jones V., Cox E. J., Jüttner I. Cocconeis pediculus Ehrenberg; 1838; 194. In: Jüttner I., Bennion H., Carter C., Cox E.J., Ector L., Flower R., Jones V., Kelly M.G., Mann D.G., Sayer C., Turner J. A., Williams D.M.. Freshwater Diatom Flora of Britain and Ireland. Amgueddfa Cymru - National Museum Wales. Available online at https://naturalhistory.museumwales.ac.uk/diatoms/browsespecies.php?-recid=3340. [Accessed:  ].

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Record last modified: 27/12/2020